The present invention relates to an automatic rewinding camera wherein a motor is automatically reversed to rewind a photographic film when the film is prevented from further advance, that is, when the film is fully withdrawn from its cartridge.
Motor driven cameras which have an electric motor built in for advancing and/or rewinding a photographic film are well known in the art. In such motor driven cameras, there is the advantage that the photographer is required only to depress the shutter release button for releasing the shutter and advancing the photographic film, and is not obliged to maintain a rewind button depressed. An automatically rewinding apparatus for cameras is disclosed in Japanese utility model application No. 53-93128 and is adapted automatically to rewind the photographic film after detecting that the photographic film is fully exposed. In this camera, a timer circuit provides an active time shorter than the time required for advancing the film one frame. A motor which is built into the camera is reversed after the lapse of the time provided by the timer circuit. As the photographic film has one end fixed to a spool shaft in the cartridge, the photographic film is prevented from further advance when it is fully exposed. Consequently the timer circuit becomes operative to reverse the motor after the lapse of the active time. However, the perforations along the film are often torn by the drive sprocket wheel when the film is prevented from further advance. Furthermore, since the drive sprocket wheel continues to rotate, false film running signals are produced so as to maintain the motor rotating in the film advance direction although the film is prevented from advancing, and thus the film rewinding operation will not be initiated. This will cause the photographer to believe he still has unexposed film, and to miss the exposures he attempts to make while under this false impression.